The day may come when the diamonds adorning red-carpet celebrities come from a factory in Florida rather than a mine in Liberia, but don't expect a huge paradigm shift just yet.

Synthetic-diamond makers received a boost in January when the Gemological Institute of America--the organization that invented the color, cut, clarity and carat diamond standards 50 years ago--began grading the quality of lab-grown diamonds.

"It gives validity to what investors and manufacturers of gems have been saying for a number of years," said Stephen Lux, CEO of Gemesis Diamond in Sarasota, Fla. "The alternative of lab-grown diamonds is a reality, and these diamonds are a nice value as compared to mined stones, which are becoming scarce."

It takes Gemesis four days to grow a diamond of an average 2.5 carats. The process begins by placing a microscopic diamond grain into a 4,000-pound machine about the size of a kitchen oven. Under hundreds of thousands of pounds of pressure and at temperatures as high as 2,700 degrees Fahrenheit, the nugget grows, one atom at a time. It uses about 20 kilowatt-hours per carat, said Reza Abbaschian, a materials scientist who helped the company develop its process.

For now, most cultivated diamonds come in colors, the natural counterparts of which are rare in nature and pricey in stores. Gemesis specializes in yellow diamonds that get their tint from a boost in nitrogen. Gemesis' Lux estimates the potential market for yellow diamonds alone to be in the tens of millions of dollars. He hopes to create more colorful and larger gems over the next five years.

Apollo Diamond produces colorless stones from a quarter carat to a half carat in size. The company spent the better part of a decade refining a method that already created the kind of thin diamond film that gives scalpels and industrial tools a stiff coating.

If you cultivate it, will they buy?
As far as aesthetics go, consumers shouldn't see any difference. Both mined and synthetic diamonds are chemically identical. Neither the naked eye, nor an ordinary microscope can detect the difference. Jewelers can tell with a loupe by reading a laser inscription required by the Federal Trade Commission. Otherwise, it takes high-tech equipment that analyzes the crystal structure of diamonds (like a proprietary machine De Beers has) to distinguish the difference.

Where some consumers may see a benefit to synthetic diamonds, however, is in the environmental and political arenas. Bryant Linares, CEO of diamond maker Apollo Diamond, anticipates that lab-grown gems will fill a niche in the jewelry market for shoppers wary of the ecological harms of mining, as well as the cost in human lives exacted by the illicit diamond trade in Africa. Mining removes several hundred tons of earth to extract one carat worth of diamond. Amnesty International estimates that 3.7 million people have died in Africa in conflicts involving the smuggling of diamonds to fund rebel armies.

And there is a cost benefit for consumers as well. After being polished, cut and set into jewelry, the synthetic stones cost about 15 percent less than comparable mined diamonds.

Indeed, Gemesis is seeing rapid growth. It adds a new diamond pressure-cooker to its collection of hundreds every few days. Having tripled diamond production since last summer, Lux plans to further expand its 10,000-square-foot operation later this year.

Several brick-and-mortar jewelry stores, as well as online merchants, carry Gemesis gems. But not everyone has taken a shine to the lab-made gems. Tiffany and other elite jewelers snub the diamond synthetics. And the jewelry industry continues to debate whether lab-grown diamonds deserve to be dubbed "cultured," like pearls.

Others say the ethical incentives are exaggerated. Only about 5 percent of people who watched the film Blood Diamond, which showed the ugly side of the mined-diamond trade, said they would change their buying habits to avoid so-called conflict diamonds, according to the Jewelry Consumer Opinion Council.

And because the diamond industry has improved its practices at tracking the source of each stone through the Kimberley Process, shunning mined diamonds for human rights reasons is short-sighted, said Rob Bates, senior editor at Jewelers Circular Keystone magazine.

Bates and others believe that lab-grown diamonds don't live up to their hype, and that it could take them a lifetime to pose a viable alternative to mined gems in jewelry.

"There are barely any out there, and those that are out there are mostly fancy, colored diamonds at high prices," he said. "We are not only not there yet; we are not even close to there."

Like Bates, other industry observers argue that the demand for man-made diamonds likely exceeds the supply. "I'd be surprised if there were more than 10,000 carats in single stones in existence," said Liz Chatelain, president of the marketing firm that runs the JCOC. "Ten years from now, when the technology is in place and there's a market around it, it might make a difference enough to really infiltrate the market."

Lab-grown diamonds may fill a niche, especially for shoppers seeking colored stones, but they won't likely replace mined diamonds in the most prized jewelry, said Chatelain. "If there's something that took 3 billion years and something that took three weeks to make, you're going to prize 3 billion."

That doesn't stop the diamond makers from dreaming. For now, only start-ups such as Gemesis and Apollo appear to be producing them for jewelry, though De Beers' Element 6 division has made industrial diamonds for decades. Diamond makers look forward to the expected surge in demand for diamonds from the developing world, particularly China and India. The relatively low cost of launching a synthetic diamond mine against the billion dollars it takes to carve a new mine from the ground could benefit companies like Gemesis and Apollo over the long term, experts say.

"Man-made diamonds will be with us in many different ways we can only begin to imagine right now that will materially affect everybody on the planet," said Apollo's Linares.

For instance, as microprocessors continue to become hotter, faster and smaller in accordance with Moore's Law, diamonds could substitute heat-sensitive silicon. The thermal conductivity, stiffness and transparency of diamonds also make them attractive for next-generation optics, digital data storage and in nanotech medical devices. And much further into the future, Linares imagines that diamond components could even clean up toxic waste and lead to ultra-efficient, compact solar panels.